Trimethinecyanine dyestuffs



Patented July 25, 1944 TRDVIET'HINEGYANINE DYlESTUFFS Karl Kumetat, Wolfen, Kreis Bitterfeld, and

Oskar Riester, Dessau-Haid'eburg, Germany, assignors to General Aniline & Film' Corporation, New York, N. Y., a corporation of Dela-..

ware

No Drawing. Application February 17, 1942, Se-

rial No. 431,268. 1940 4 Claims.

Our present invention relates to trimethinecyanine dyestuffs and more particularly to a new method of the production thereof.

Symmetrical and unsymmetrical trimethinecyanines are known to be obtained by reacting anilinovinyl' compounds of the general formula:

or 2-methene-w-aldehydes of the general formula:

alkyl wherein R stands for hydrogen, alkyl or acetyl; Z stands for a group of atoms necessary to complete a 5 or 6-membered ring usual in cyanine dye art, and X stands for an anionic acid radical; with quaternary salts of similar or diiferent heterocyclic compounds containing a reactive alkyl group. These methods cannot be employed in all' cases. Unsymmetrical benzimidazoletrimethinecyanines, for instance, can be prepared only by means of compounds of Formula II. In many cases, however, there is reached only a moderate yield. As to other dyestuffs, for instance, some unsymmetrical benzoxazoletrimethinecyanines there is obtained not only a very small yield but impure products as well due to the presence of symmetrical dyestuffs when resorting to. the process involving the compounds ofFormula II. In this case the production of the cyanines has been accomplished by means ofcompounds of Formula I. 'But' this process also often results in moderate yields.

We have found that symmetrical and unsymmetrical trimethinecyanines are obtained more easily and with a better yield by reacting compounds. corresponding to the general formula:

wherein Z means a group of atoms necessary to complete a 5- or 6-membered ring usual in the cyanine dye art as, for instance, indoline, oxazole, thiazole,- selenazole, oxazoline, thiazoline, selenazoline, pyridine, lepidine, imidazole, quinoline or In Germany September 17,

thiodiazole; these heterocyclic radicals may carry substituents such as alkyl, aryl, benzyl, phenylene, naphthylene and substituted phenyls or heterocyclic radicals or may be condensed with aromatic or heterocyclic rings; R1 and R2 mean alkyl or aralkyl, and X means an. anionic acid radical, for instance, Cl, Br, I, 0104, S04, SO3CH3, SOsCzHs, SO3CsI-I4.CH3; with quaternary salts 'Of similar or different heterocyclic nitrogenous compounds containing a reactive alkyl group-in the ozor 'y-position to the nitrogen atom in the presence of an alkaline condensing agent-as, for instance, pyridine, quinoline, isoquinoline, picoline or amines such as triethylamine. The compounds of Formula III serving as starting materials may be prepared by the process described in U. S. Patent No. 2,349,179. From some quaternary salts of heterocyclic bases as, for instance, the addition products of w-halogen-fatty acids to heterocyclic bases pure crystallized dyestuffs can be obtained in a sufficient yield only by compounds of Formula-III.

The following examples. illustrate the present invention but they are'not intended to limitit thereto.

Example-1 A yestuff of the following formula;

2 5 (3H Cl HaCC--- Q] '-CH=CH-CH= 0104 OCOCH3 are added thereto. The whole is boiled for minutes and then cooled. The dyestufi is precipitated with an aqueous sodium perchlorate solution of 20% strength. The dyestuff is re- Absorption maxicrystallized from methanol. mum in methanol: 490 m -520 m i Example 2 A dyestuff of the following formula:

int (3H3 Cl Hioc- NV \N/ 2610 Hi), on;

is obtained in a manner analogous to that as described in Example 1 by using as the quaternary heterocyclic compound /100 mol of 2.3-dimethyl- 1 -(trimethylammoniumpropyl) -5 chlorobenzimidazoliummethylsulfate. Absorption maximum in methanol: 485-510 m Example 3 A dyestuff of the following formula:

05H, om o1 7 Biol-r'zoi "Q N 20104- (Hz); 41H:

moi-N10110:

is produced in a manner analogous to thatas described in Example 1 by using as the quaternary heterocyclic compound a, quaternary salt of the following constitution:

C1 C'GHa iHCzN' (CH a) f Absorption maximum in methanol: 490-520 ml. Example 4 A dyestuff of the following formula:

CH: CH:

is prepared as follows: A mixture of ,5 mol of 2-methyl-5-methoxybenzoxazoleethyliodide and ,4 mol of a compound of the following formula: 0

is prepared in the following manner: A mixture of 4 g. of the addition product of p-bromopropionic acid, to 2.5.S-trimethylbenzoxazole of the following formula:

HaC O a CH OOH

and 3.4 g. of 1.3.3.5-tetramethyl-2-(oi-methylmercapto)-etheneindoliniumperchlorate corresponding with the second formula of Example 4 is heated with 10 cc. of pyridine at 100 C. for

minutes. On addition of cc. of a 4-normal aqueous sodium perchlorate solution and 30 cc. of acetic acid of 10% strength the dyestuff is caused to crystallize out. 7 It is recrystallized from propanol. Absorption maximum in methanol:

Example 6 A dyestufi of the following formula:

HzC O CH:

OOH

is prepared as follows: A mixture of the benzoxazole addition product mentioned in Example 5 and 3 g. of N -ethyl-2 (w-methylmercapto) -ethenethiazoliniumperchlorate of the formula:

CiHi

; is heated with 10 cc. of pyridine at 100 c. for

minutes. After addition of 10 cc. of a -normal aqueous perchlorate solution and cc. of acetic acid of 10% strength the .whole is cooled with ice for 5 hours. The precipitated dyestuif is recrystallized from methanol. Absorption maximum in methanol: 476 m Example 7 A dyestufi of the following formula:

Se c-oH=oH -oH L N N OH; H:

00011 7 is obtained in the following manner: A mixture of 4 g. of the addition compound from p-iodopropionic acid and Z-methylbenzselenazole of the formula:

and 3.3 g. of l.3E3 triirithyl-2 -w methylrnrcapto) etheneindoliniumperchlorate is heated with cc. of pyridine and 1 cc. .of triethylami ne at 105 C. for half an hour; To the hot solution there are added 3 0, cc.'of an aqueous sodiiii'n perchlorate solution of 50% strength and 40;;cc. of acetic acid of 10% strength. The dyestuff 'obtained form green lustrous crystals and is recrystallized from; methanol. Absorption maximum in methanol: 55011111..

Example 8 ;dyastufi-.o'fvtheq ormul zr i is produced in the following manner: A mixture of 3.3 g. of the addition compound from p-bron'fiopropionic acid and Z-methylbenzthiazole ofthe formula:

1 coon and 3.3 g. of 1.3.3-trimethyl-2-(w-methylrnercapto) etheneindoliniumperchlorate is heated with 10 cc. of pyridine at 105 C. in an oil bath for half an hour. On addition of 30' cc. of a 4- normal aqueous sodiumperchlorate solutionand cc. of acetic acid of 10% strength the dystufi is caused to crystallize. It is recrystallized i'r'om propanol. Absorption maximum in methanol: 545 mu.

Example 9 A dyestufi of the formula:

C111 CH3 is obtained by heating mol of quinaldine ethyliodide with /100 mol of 1.3.3.5-tetramethyl- 2- (w-methylmercapto) -etheneindolinium ethyliodide in a mixture of pyridine and triethylamine at 70 C. Absorption maximum in methanol: about 590 m We claim:

1. A process of preparing trimethinecyanines which comprises reacting compounds of the general formula:

wherein Z means a group of atoms necessary to complete a ring usual in the cyanine dye art,

HsCrN' (CH3) 2" v which comprises reacting a compoundi of the formula: (13H;

CCHa

O'OH=CHS-CHa with a compound of the formula:

in the presence of a mixture of pyridine and triethylamine and precipitating the dyestufi with sodiumperchlorate.

3. A process of preparing a trimethinecyanine dyestufi of the formula:

which comprises reacting a compound of the formula:

with a compound of the formula:

HaC -O e COOH H30 Br" in the presence of pyridine and precipitating the dyestufi with a sodiumperchlorate.

a. A brocess 0t Pr-ennring a trimethineyanine with a compound orv the: termula: (immoflhevmrmmazr- .7

h m comprises "acting a command the in the presence of pyridine and precipitating the m 15 dyestuff with sodiumperchlorate.

KARL mmm'm'r. OSKAR Rmsm. 

